Nokea
The processes of chewing are referred to as _____.
- A. churning
- B. mastication
- C. peristalsis
- D. deglutition
Correct Answer: B
Rationale: The correct answer is B: mastication. Mastication refers to the mechanical process of chewing food in the mouth using the teeth and jaws. This process breaks down food into smaller pieces, making it easier to swallow and digest. Churning (A) is the mixing of food with digestive enzymes in the stomach. Peristalsis (C) is the involuntary muscle contractions that move food through the digestive tract. Deglutition (D) is the process of swallowing food. Mastication is the most appropriate term for the process of chewing specifically.
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Which of the following statements about fat and fat digestion/absorption is true?
- A. Fat soluble vitamins are incorporated into mixed micelles and absorbed directly across the microvillus cell membrane
- B. Triglycerides are resynthesized from fatty acids and monoglyceride in the intestinal epithelial cell and are exported directly into the portal circulation
- C. Pancreatic lipase functions best at a pH of 3
- D. None of the above
Correct Answer: D
Rationale: The correct answer is D because none of the statements are true. A is incorrect because fat-soluble vitamins are incorporated into chylomicrons before absorption. B is incorrect because triglycerides are resynthesized in the intestinal cell but packaged into chylomicrons, not directly exported. C is incorrect because pancreatic lipase functions best at a pH of around 7-8, not 3. So, the correct answer is D as all the other choices are incorrect.
Which of the following statements is TRUE? The protein FOXO1:
- A. activates (increases the expression of) genes related to greater longevity
- B. is activated by caloric restriction
- C. is deactivated by increased insulin signalling
- D. all of the above are true
Correct Answer: D
Rationale: Step-by-step rationale:
1. FOXO1 activates genes related to greater longevity by regulating stress responses and promoting cell survival.
2. Caloric restriction activates FOXO1 to promote cellular stress resistance and increase lifespan.
3. Increased insulin signaling deactivates FOXO1, leading to decreased stress resistance and potentially shorter lifespan.
4. Therefore, all the statements (A, B, and C) are true regarding the protein FOXO1. It plays a crucial role in longevity through gene regulation, is activated by caloric restriction, and is deactivated by increased insulin signaling.
Which statement about the oral phase of digestion is INCORRECT?
- A. About 2% of the energy content of food is expended during the action of chewing and swallowing it.
- B. Swallowing involves contraction and relaxation of at least 14 groups of muscles in about 10 seconds in healthy subjects
- C. The biofilm covering tooth enamel contains several salivary and bacterial enzymes
- D. Salivary amylase digests the dextran film on tooth enamel formed from dietary sucrose
Correct Answer: D
Rationale: Correct Answer: D
Rationale: Salivary amylase primarily digests carbohydrates in the oral cavity, breaking down starch into simpler sugars like maltose. It does not directly target the dextran film on tooth enamel formed from dietary sucrose. This film is typically broken down by dental plaque bacteria, not salivary amylase. Therefore, option D is incorrect.
Summary of Incorrect Choices:
A: This statement is correct. Chewing and swallowing do require energy expenditure.
B: This statement is correct. Swallowing involves the coordinated action of multiple muscle groups.
C: This statement is correct. The biofilm on tooth enamel contains enzymes from both saliva and bacteria, contributing to oral digestion.
You take a deep breath; you raise your larynx and hyoid bone; your epiglottis closes off the larynx; the soft palate closes off the nasopharynx; the diaphragm and abdominal muscles contract and the lower esophageal sphincter relaxes. What has just happened?
- A. Low blood glucose levels caused these hunger pangs.
- B. Irritation in the GI tract caused the vomiting reflex.
- C. Bolus has entered the larynx and stimulated the gagging reflex.
- D. Bolus has entered the oropharynx, which initiated the swallowing reflex.
Correct Answer: D
Rationale: The correct answer is D because the described sequence of events matches the process of swallowing. Raising the larynx and hyoid bone helps to protect the airway, closing the epiglottis prevents food from entering the trachea, closing the soft palate blocks the nasopharynx to prevent food from entering the nasal cavity, and the contraction of the diaphragm and abdominal muscles along with relaxation of the lower esophageal sphincter facilitate the movement of food into the esophagus. This series of actions is characteristic of the swallowing reflex.
Choices A, B, and C are incorrect. Low blood glucose levels do not directly trigger the swallowing reflex. Irritation in the GI tract would not lead to the described sequence of events. Bolus entering the larynx or nasopharynx would not be part of the normal swallowing process and would typically trigger the gagging reflex instead.
Patients with a paralytic ileus typically have:
- A. Intravenous fluid replacement and a nasogastric tube connected to suction.
- B. Surgical correction of the problem.
- C. Endoscopic injection of botulinum toxin or esophageal dilation.
- D. Endoscopy to allow biopsy followed with broad-spectrum antibiotics.
Correct Answer: A
Rationale: Paralytic ileus is typically managed with intravenous fluids to correct electrolyte imbalances and a nasogastric tube to decompress the bowel.